Virtualization is a very popular technology, but has been held back from further use by two factors: cost and hardware load. The most popular virtualization product is VMWare from EMC. It is widely regarded as an excellent product, but it expensive. Its cost has kept it out of reach for many organizations.
Setting cost aside, most previous virtualization products have imposed performance penalties on the virtual operating systems. Put more simply, an application executing within a virtual OS performs poorly compared with the same application running on a native OS. This performance hit is caused by the intervening levels of software interposed between the application and the underlying native OS.
There is a product that can address both virtualization problems: Xen. Xen is a small (< 50 KLOC) virtualization product available under open source license. Due to its small size and clever engineering, Xen imposes far less of a performance penalty on running applications than other virtualization products.
This was first published in May 2006